A California university professor can no longer demand snacks from students taking his psychology classes.

Sacramento State professor George Parrott has demanded snacks from his students for 39 years. Students were told of the snack demand on the first day of class. But two weeks ago he walked out of his Psychology 101 lab class because there were no snacks.

University spokeswoman Kimberly Nava says members of the psychology department at California State University, Sacramento decided Parrott's decision to walk out of class was unacceptable and the dean told him to stop.

The Sacramento Bee ( http://bit.ly/uFUlfJ) reports Parrott's requirement was his way of encouraging students to work collectively, among other things.